Venturi-style eductors used to educt a second fluid into a primary motive fluid stream are established fluid handling devices and are used commonly in industrial applications, cleaning applications, and food services. A typical such device may be found in Thompson, U.S. Pat. No. 4,508,272. Common to any such device is an inlet orifice for a motive stream, most often water, where the diameter of the inlet orifice is larger than the smallest diameter in a converging flow-path. Immediately downstream of the converging flow-path is a mixing zone having a diameter larger than the smallest restriction in the converging zone. Transverse to the motive flow path, a port is tapped into an eductor body such that an eduction flow path communicates with the motive flow path at the mixing zone. Bernoulli's equation demonstrates that suction is created in the mixing zone allowing a second solution to be drawn, or educted, into the mixing zone. It is through this transverse path that suction draws mentioned second fluid into the mixing zone whereby the second fluid and motive fluid become mixed. Downstream from the mixing zone the flow path diverges or widens in cross-section to conduct the mixture of motive fluid and educted second fluid to the eductor outlet.
Traditional venturi-style eductors are assembled using multiple components to comprise the main body of the device. Prior art focuses on using machined eductor components from metallurgies resistant to chemical attack and corrosion. Machinable stainless steel and brass are most common. Given the complex geometry a venturi flow path and the limitations of machining technology, multiple parts are manufactured and then assembled to create the main body of an eductor. While such devices work satisfactorily they are costly to manufacture and have limitations with respect to the flow path geometry. Some chemical applications require the use of a chemical that is not suited to available metallic eductors considering corrosion potential constituting a further limitation.
Prior art does mention venturi-style eductors having molded integral components as in Sand U.S. Pat. No. 5,522,419 though in this invention reveals wetted brass surfaces and multiple machined components.